Place cola in a Dutch oven or large saucepan and boil over medium-high heat until reduced to 1 1/2 cups, about 45 minutes.
Add next 6 ingredients and stir well. Reduce heat to medium and simmer until reduced to 2 1/2 cups, stirring occasionally. This will take about 35 minutes. Remove from heat.
Place oven racks in top and bottom thirds of oven and heat oven to 325 degrees.
Season ribs with salt and pepper. Wrap each rack tightly in foil. Divide ribs between 2 baking sheets and place in oven for 2 hours. Let ribs cool slightly.
Heat grill to medium heat.
Cut racks of ribs into individual ribs. Toss with 1 cup of glaze.
Grill ribs, basting with extra glaze, for about 2 to 3 minutes per side.
Serve with extra glaze.
Notes
If possible, use flat soda or pour it into a bowl and let it sit on the counter for 4 hours. But it is ok to skip this step.Recipe adapted from Epicurious (published in Bon Appetit)